1. Field of the Invention
The present invention relates to a substrate treatment apparatus and a substrate treatment method for treating a substrate. Examples of the substrate to be treated include semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma display devices, substrates for FED (Field Emission Display) devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photo masks, ceramic substrates, and substrates for solar cells.
2. Description of the Related Art
In production processes for semiconductor devices and liquid crystal display devices, substrates such as semiconductor wafers and glass substrates for liquid crystal display panels are treated with a treatment liquid. A substrate treatment apparatus of a single substrate treatment type adapted to treat a single substrate at a time includes, for example, a spin chuck which horizontally holds and rotates the substrate, a bifluid nozzle which causes droplets of a treatment liquid to impinge on an upper surface of the substrate held by the spin chuck, and a rinse liquid nozzle which spouts a rinse liquid toward the upper surface of the substrate held by the spin chuck. In the substrate treatment apparatus, the substrate is cleaned by causing the treatment liquid droplets to impinge on the upper surface of the substrate while covering the upper surface of the substrate with the rinse liquid.
In a substrate treatment apparatus disclosed in U.S. Patent Application Publication No. US 2003/0084925 A1, the bifluid nozzle spouts the treatment liquid toward a certain region (hereinafter referred to as “spouting region”) on the upper surface of the substrate. A part of the rinse liquid supplied to the substrate spreads toward the spouting region on the substrate. However, the rinse liquid flowing to the spouting region is prevented from entering the spouting region by the treatment liquid droplets, because the treatment liquid droplets are vigorously sprayed on the spouting region. Therefore, the rinse liquid hardly reaches the spouting region, failing to form a sufficiently thick rinse liquid film on the spouting region. Therefore, the treatment liquid droplets are sprayed on the spouting region which is not covered with the liquid film or is covered with a thin liquid film. The impingement of the liquid droplets on the substrate results insignificant impact on a pattern formed on the substrate, causing damages such as collapse of the pattern.